An example of an electromagnetic relay belonging to the prior art is shown in FIG. 16. This relay comprises electromagnetic block 1, which is formed by wrapping coil 1c around two facing L-shaped cores, 1a and 1b; H-electrode 2b, which rotates shaft 2a on its axis in response to the presence or absence of excitation in electromagnetic block 1; transmission mechanism 3, which travels back and forth with the rotation of H electrode 2b; and contact mechanism 6, in which the movement of transmission mechanism 3 causes movable contacts 4a on members 4 to come in contact with or move away from fixed contacts 5a on members 5.
7 is a spring mounted on support 8 to return mechanism 3 to its original position.
In the electromagnetic relay which we have been discussing, contact mechanism 6 is driven by H electrode 2b and transmission mechanism 3, a scheme which requires a large number of components. This entails a large number of assembly processes and increases the likelihood that the precision with which the components are assembled, and hence the operating characteristics, will vary.
Also, in this relay electromagnetic block 1, H electrode 2b and contact mechanism 6 are arrayed in a linear fashion, which tends to increase the length of the relay. Since the length of contact mechanism 6 will increase with the number of circuits, it will be impossible to produce a short electromagnetic relay if there are a large number of circuits to make and break.